I think the character that changed the most would have to be Claude. Claude went from an arrogant, vain, selfish, inconsiderate, rude, mean, and disrespectful towards other peoples religion, into a kind man who treats his animals kindly, is hospitable towards travelers,and no longer looks down on The Green Man or the peasants that leave food for him.
Gonta didn't change much because it said in the story that Ooka knew him as a hardworker. So his perspective may have changed from okay, to disappointed, to sympathetic, because Ooka knew him before as a hard worker and didn't think much about him. Ooka was disapppointed in him because he stole from the rice guy. And he was sympathetic because he felt bad Ooka was such a hardworker and that he had a family to provide for so he gave Gonta a job.
Scho, from "A Game Of Catch" went from being a lonely little boy that just wanted to play with the other kids, to an over-confident, little poop that takes advantage of other kids.
I think that The Valiant Little Tailor was pretty full of himself before he killed the seven flies but this was the first time he had a chance to show the world how "great" that he was.
I think that Laurie was always pretty devious but his parents didn't notice because he was always their perfect little angel.